Description

Parameters

hostname

hostname should be a valid DNS hostname such
as "www.example.com". Reverse lookups can be generated
using in-addr.arpa notation, but
gethostbyaddr() is more suitable for
the majority of reverse lookups.

Note:

Per DNS standards, email addresses are given in user.host format (for
example: hostmaster.example.com as opposed to hostmaster@example.com),
be sure to check this value and modify if necessary before using it
with a functions such as mail().

type

By default, dns_get_record() will search for any
resource records associated with hostname.
To limit the query, specify the optional type
parameter. May be any one of the following:
DNS_A, DNS_CNAME,
DNS_HINFO, DNS_MX,
DNS_NS, DNS_PTR,
DNS_SOA, DNS_TXT,
DNS_AAAA, DNS_SRV,
DNS_NAPTR, DNS_A6,
DNS_ALL or DNS_ANY.

Note:

Because of eccentricities in the performance of libresolv
between platforms, DNS_ANY will not
always return every record, the slower DNS_ALL
will collect all records more reliably.

authns

Passed by reference and, if given, will be populated with Resource
Records for the Authoritative Name Servers.

addtl

Passed by reference and, if given, will be populated with any
Additional Records.

raw

In case of raw mode, we query only the requestd type instead of looping
type by type before going with the additional info stuff.

Return Values

This function returns an array of associative arrays,
or FALSE on failure. Each associative array contains
at minimum the following keys:

Basic DNS attributes

Attribute

Meaning

host

The record in the DNS namespace to which the rest of the associated data refers.

class

dns_get_record() only returns Internet class records and as
such this parameter will always return IN.

type

String containing the record type. Additional attributes will also be contained
in the resulting array dependant on the value of type. See table below.

ttl

"Time To Live" remaining for this record. This will not equal
the record's original ttl, but will rather equal the original ttl minus whatever
length of time has passed since the authoritative name server was queried.

target: FQDN of location in DNS namespace to which
the record is aliased.

NS

target: FQDN of the name server which is authoritative
for this hostname.

PTR

target: Location within the DNS namespace to which
this record points.

TXT

txt: Arbitrary string data associated with this record.

HINFO

cpu: IANA number designating the CPU of the machine
referenced by this record.
os: IANA number designating the Operating System on
the machine referenced by this record.
See IANA's » Operating System
Names for the meaning of these values.

SOA

mname: FQDN of the machine from which the resource
records originated.
rname: Email address of the administrative contain
for this domain.
serial: Serial # of this revision of the requested
domain.
refresh: Refresh interval (seconds) secondary name
servers should use when updating remote copies of this domain.
retry: Length of time (seconds) to wait after a
failed refresh before making a second attempt.
expire: Maximum length of time (seconds) a secondary
DNS server should retain remote copies of the zone data without a
successful refresh before discarding.
minimum-ttl: Minimum length of time (seconds) a
client can continue to use a DNS resolution before it should request
a new resolution from the server. Can be overridden by individual
resource records.

AAAA

ipv6: IPv6 address

A6(PHP >= 5.1.0)

masklen: Length (in bits) to inherit from the target
specified by chain.
ipv6: Address for this specific record to merge with
chain.
chain: Parent record to merge with
ipv6 data.

SRV

pri: (Priority) lowest priorities should be used first.
weight: Ranking to weight which of commonly prioritized
targets should be chosen at random.
target and port: hostname and port
where the requested service can be found.
For additional information see: » RFC 2782

NAPTR

order and pref: Equivalent to
pri and weight above.
flags, services, regex,
and replacement: Parameters as defined by
» RFC 2915.

Changelog

Version

Description

5.4.0

Added raw parameter.

5.3.0

This function is now available on Windows platforms.

5.3.0

Prior to this release, if the authns parameter
was given, the addtl parameter was also
required.

Since it's very common to want the IP address of a mail server
once the MX record has been resolved, dns_get_record()
also returns an array in addtl which
contains associate records. authns
is returned as well containing a list of authoritative name
servers.

Get more than one type at once like this:<?php$dnsr = dns_get_record('php.net', DNS_A + DNS_NS);print_r($dnsr);?>

Using DNS_ALL fails on some domains where DNS_ANY works. I noticed the function getting stuck on the DNS_PTR record, which caused it to return FALSE with this error:PHP Warning: dns_get_record(): res_nsend() failed in ....